about Set and List
Set<T> set;
List<T> list
in which case will appear
1. set != null && set.size==0
2. list!=null && list.size()==0
thx!
[解决办法]
set.size 貌似这个错了
[解决办法]
应该都==null，没有new 吧！！
[解决办法]
Set<T> set; //set==null
set = new HashSet(); //set != null && set.size==0
List<T> list; //list==null
list = new ArrayList(); //list != null && list.size==0
[解决办法]
接3L
set.add(new T()); //set != null && set.size!=0
list.add(new T()); //list!= null && list.size!=0
